[libvirt] [PATCH] Avoid crash in security driver if model is NULL

[Daniel P. Berrange]

If the XML security model is NULL, it is assumed that the current
model will be used with dynamic labelling. The verify step is
meaningless and potentially crashes if dereferencing NULL

* src/security/security_manager.c: Skip NULL model on verify
---
 src/security/security_manager.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/src/security/security_manager.c b/src/security/security_manager.c
index 66cffb5..1bc0ebb 100644
--- a/src/security/security_manager.c
+++ b/src/security/security_manager.c
@@ -309,6 +309,13 @@ int virSecurityManagerSetProcessLabel(virSecurityManagerPtr mgr,
 int virSecurityManagerVerify(virSecurityManagerPtr mgr,
                              virDomainDefPtr def)
 {
+    /* NULL model == dynamic labelling, with whatever drive
+     * is active, so we can short circuit verify check to
+     * avoid drivers dereferencing NULLs by accident
+     */
+    if (!secdef->model)
+        return 0;
+
     if (mgr->drv->domainSecurityVerify)
         return mgr->drv->domainSecurityVerify(mgr, def);
 
-- 
1.7.3.4